KR101512543B1 - Baseband processor with peak suppression function, transmitter with the same and method of transmitting signal - Google Patents

Abstract

The present invention relates to a baseband processor having a peak suppression function, a transmission apparatus, and a transmission method. A baseband processor according to an embodiment of the present invention includes: a signal generator for generating a digital signal; A variable up / down sampling unit for varying a sampling rate in real time according to a size of a signal bandwidth varying in real time and sampling a digital signal from the signal generating unit according to the sampling rate; A peak detector for detecting the peak power of the sample signal from the variable up / down sampling unit for each section in which the peak exists, and for suppressing the peak power of the sample signal using an inhibition factor determined according to the section peak power, Suppression processing unit; And a signal conversion unit for converting a digital signal from the peak suppression processing unit into an analog signal, wherein the peak suppression processing unit can suppress the corresponding peak power of the sample signal through a clipping window generated according to the suppression factor .

Description

TECHNICAL FIELD [0001] The present invention relates to a baseband processor having a peak suppression function, a transmission apparatus, and a transmission method.

The present invention relates to a baseband processor which can be applied to an OFDM-based communication system and can suppress a peak power suppression of a transmission signal by using a variable sampling rate and window clipping , A transmission system, and a transmission signal processing method.

Generally, one of the biggest disadvantages of communication modulation applied to orthogonal frequency-division multiplexing (OFDM) based communication systems such as LTE (Long Term Evolution) and WiMax (Worldwide Interoperability for Microwave Access) Peak to Average Power Ratio (PAPR or PAR). This is because the efficiency of the linear power amplifier is degraded by the high PAPR (or peak). Thus, over the past decade, numerous PAPR suppression (PAPR suppression, or peak suppression) methods have been researched and developed.

Among the existing PARP suppression methods, the most efficient and easy to implement method is a method using windowed clipping. This PAPR suppression technique can be applied to an OFDM-based communication system without changing any protocol or standard signal generation process.

In recent OFDM-based communication systems such as OFDMA and Single-Carrier-Frequency-Division Multiple Access (SC-FDMA), the bandwidth of a signal may change in real time depending on the usage environment. Thus, the thickness of a signal having a typical peak power can be significantly changed. However, if the window size is fixed as in the conventional method, PAPR can not be effectively suppressed.

Further, when the bandwidth of the communication signal is wide, in an OFDM-based communication system, the original sampling rate of the signal may not be high enough to measure information of a signal having a peak. In this case, the windowed clipping ) There is also a problem that the efficiency of the method may fall more seriously.

On the other hand, when the bandwidth of the communication signal is narrow, the original sampling rate is higher than necessary, and in this case the windowing clipping complexity can be reduced without lowering the performance by lowering the sampling rate.

Therefore, when the bandwidth of the communication signal changes greatly in real time, there arises a problem of window size, information detection problem of an incorrect peak, and complexity.

The following Patent Document 1 discloses that the PAPR can be effectively suppressed by reducing the spectrum distortion, which is a problem in the prior art, regarding the "low splatter peak-to-average signal reduction." However, , The peak signal can not be accurately measured unless the sampling rate is sufficiently large, so that the performance may be deteriorated.

The following Patent Document 2 relates to a "low-splatter peak-to-average signal reduction with interpolation". When interpolation is performed on a signal having a peak when the sampling rate is not sufficiently large, However, there is a problem in that it is more complicated to implement due to the complexity of the signal processing, and there is also a problem in that the OFDMA-based There is a problem in the communication system that it is impossible to solve the disadvantage that the window size problem or the sampling becomes too much in real time.

U.S. Patent No. 5,287,387 U.S. Patent No. 5,638,403

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to suppress peak power suppression of a transmission signal by using a variable sampling rate and window clipping A baseband processor, a transmission system, and a transmission signal processing method.

According to a first technical aspect of the present invention, there is provided a signal processing apparatus comprising: a signal generating unit for generating a digital signal; A variable up / down sampling unit for varying a sampling rate in real time according to a size of a signal bandwidth varying in real time and sampling a digital signal from the signal generating unit according to the sampling rate; A peak detector for detecting the peak power of the sample signal from the variable up / down sampling unit for each section in which the peak exists, and for suppressing the peak power of the sample signal using an inhibition factor determined according to the section peak power, Suppression processing unit; And a signal conversion unit for converting a digital signal from the peak suppression processing unit into an analog signal, wherein the peak suppression processing unit includes: a base band suppressing a corresponding peak power of the sample signal through a clipping window generated according to the suppression factor; Processor.

According to a second aspect of the present invention, there is provided a digital signal processing apparatus comprising: a signal generator for generating a digital signal; A variable up / down sampling unit for varying a sampling rate in real time according to a size of a signal bandwidth varying in real time and sampling a digital signal from the signal generating unit according to the sampling rate; A peak detector for detecting the peak power of the sample signal from the variable up / down sampling unit for each section in which the peak exists, and for suppressing the peak power of the sample signal using an inhibition factor determined according to the section peak power, Suppression processing unit; A signal conversion unit for converting a digital signal from the peak suppression processing unit into an analog signal; And a RF processor for converting an analog signal from the signal converter into an RF signal, wherein the peak suppression processor comprises: a transmitter for suppressing a corresponding peak power of the sample signal through a clipping window generated according to the suppression factor; Lt; / RTI >

In the first and second technical aspects of the present invention, the variable up / down sampling unit compares a signal bandwidth varying in real time with a preset reference band width, and adjusts a sampling rate set in advance according to the comparison result in real time .

If the signal bandwidth is smaller than the reference bandwidth, the variable up / down-sampling unit lowers the sampling rate according to the signal bandwidth, and if the signal bandwidth is larger than the reference bandwidth, The sampling rate may be increased according to the size of the sample.

Wherein the peak suppression processing section comprises: a signal power calculation section for calculating a power of each of the sample signals from the variable up / down sampling section; A local peak detector for detecting a peak power for each of the peaks among the powers calculated by the signal power calculator; A suppression factor determiner for determining an inhibition factor according to the peak power per section detected by the local peak detector; And a window clipping unit for generating a clipping window according to the suppression factor from the suppression factor determination unit and suppressing the peak power of the corresponding sample signal from the variable up / down sampling unit by applying the clipping window.

The suppression factor determiner may compare the peak power with the reference power if the peak power detected by the local peak detector is greater than a predetermined reference power, and determine the suppression factor according to the comparison result.

The window clipping section may be adapted to adjust the size of the clipping window according to the thickness of the corresponding sample signal having the peak so as to minimize distortion in the spectrum and minimize degradation in bit error rate.

In addition, as a third technical aspect of the present invention for solving the problems of the present invention, there is provided a digital signal processing method comprising the steps of: generating a digital signal; Sampling the digital signal from the signal generation step according to the sampling rate, varying the sampling rate in real time according to the size of the signal bandwidth varying in real time; Detecting a peak power of a sample signal from the sampling step in each section in which a peak exists and suppressing a corresponding peak power of the sample signal using an inhibition factor determined according to the peak power per section; And converting the digital signal from the peak power suppression step to an analog signal, wherein the corresponding peak power of the sample signal is suppressed through a clipping window generated according to the suppression factor.

In the third technical aspect of the present invention, the sampling step may be performed by comparing a signal bandwidth varying in real time with a preset reference bandwidth, and varying a preset sampling rate in real time according to the comparison result.

Wherein the sampling step comprises: if the signal bandwidth is smaller than the reference bandwidth, the sampling rate is lowered according to the signal bandwidth, and if the signal bandwidth is larger than the reference bandwidth, The sampling rate may be increased.

Wherein the peak power suppression step comprises: calculating power of each of the sample signals from the sampling step; Detecting peak power for each of the peaks among the powers calculated in the peak power calculation step; Determining a suppression factor according to the peak power detected in the peak power detection step; Generating a clipping window in accordance with the suppression factor from the suppression factor determining step and suppressing the peak power of the corresponding sample signal from the sampling step by applying the clipping window.

The suppression factor determining step may be configured to compare the peak power with the reference power if the peak power detected in the peak power detection step is greater than a predetermined reference power, and to determine the suppression factor according to the comparison result.

The clipping window application step may be adapted to adjust the size of the clipping window according to the thickness of the corresponding sample signal having the peak so as to minimize distortion in the spectrum and to minimize degradation in bit error rate .

Further, the transmitting method of the present invention may include a step of converting an analog signal from the signal converting step into an RF signal.

According to the present invention, the peak power of a transmission signal can be suppressed by using a variable sampling rate and window clipping.

That is, the present invention can solve the above-mentioned problem of the size of the clipping window, the problem of information of the inaccurate peak signal, and the complexity when the signal bandwidth is changed in real time, and the windowed clipping By varying the sampling rate based on the signal bandwidth currently used, the window size can be automatically changed to match the thickness of the sample signal having the peak as the sampling rate is changed. On the other hand, downsampling can reduce the complexity of algorithm computation.

1 is a block diagram of a transmitting apparatus according to a first embodiment of the present invention;
2 is a block diagram of a peak suppression processing unit according to the first embodiment of the present invention;
3 is a flowchart of a transmission method according to a second embodiment of the present invention;
4 is a diagram of a first variable sequence of sampling rates according to an embodiment of the present invention.
5 illustrates a second, variable ordering example of a sampling rate according to an embodiment of the present invention.
6 is a flowchart of peak power suppression in accordance with an embodiment of the present invention.
7 is a descriptive graph of window clipping according to an embodiment of the present invention.
FIG. 8 is a graph illustrating a fixed sampling rate for signals of different bandwidths
9 is a graph showing the effect of increasing the PAPR and the sampling rate when the bandwidth is large
10 is an explanatory diagram of a peak suppression effect of a large sampling rate when the bandwidth is small;

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

Since the embodiments of the present invention are used to help understand the technical idea of the present invention, the present invention is not limited to the embodiments described. In the drawings referred to in the present invention, components having substantially the same configuration and function will use the same reference numerals.

1 is a block diagram of a transmitting apparatus according to a first embodiment of the present invention.

Referring to FIG. 1, a transmitting apparatus according to a first embodiment of the present invention may be applied to an OFDM-based communication system using subcarriers, and may include a baseband processor and an RF processor 500.

The baseband processor according to an embodiment of the present invention includes a signal generator 100 for generating a digital signal, a demultiplexer 110 for varying a sampling rate (SR) in real time according to the size of a signal bandwidth varying in real time, A variable up / down sampling unit 200 for sampling a digital signal from the signal generator 100 according to a sampling ratio SR and a peak power of a sample signal from the variable up / A peak suppression processing unit 300 for detecting the peak power of the sample signal PPL according to the peak power PPL and for suppressing the peak power of the sample signal according to the peak power PPL, And a signal conversion unit 400 for converting the signal into an analog signal.

In addition, the RF processor 500 may be configured to convert an analog signal from the signal converting unit 400 into an RF signal.

In this case, referring to FIG. 1, the signal generating unit 100 may generate a digital signal including data to be transmitted. At this time, the signal generator 100 can supply information on a signal bandwidth in real time.

The variable up / down-sampling unit 200 varies a sampling rate (SR) in real time according to a signal bandwidth (Bandwidth) varying in real time, and outputs the signal to the signal generator 100 Can be sampled.

That is, the variable up / down-sampling unit 200 shown in FIG. 1 has the input digital signal (I signal and / or digital signal) so as not to have a too high sampling rate, Q signal) can be sampled based on the magnitude of the signal bandwidth from the signal generator 100. [ Here, the peak information may include a peak power and a peak position.

The variable up / down-sampling unit 200 compares the digital signal from the signal generator 100 with a signal bandwidth (BW) varying in real time and a preset reference bandwidth with respect to the sampling ratio And the sampling rate SR set in advance can be varied in real time according to the comparison result.

Specifically, when the signal bandwidth is smaller than the reference bandwidth, the variable up / down-sampling unit 200 may lower the sampling rate SR according to the bandwidth, If the bandwidth is greater than the bandwidth, the sampling rate SR may be increased according to the bandwidth.

For example, when the transmission apparatus of the present invention is an LTE uplink, 72 to 1320 subcarriers may be used. Here, 72 subcarriers are 6 resource blocks, which can correspond to a bandwidth of 1.08 MHz. And 1320 subcarriers are 110 resource blocks and can correspond to a bandwidth of 19.8 MHz. However, a signal having 72 subcarriers does not need 2040 samples per symbol, unlike a signal having 1320 subcarriers.

On the other hand, a signal having 1320 subcarriers requires about 8192 samples per symbol in order to accurately detect peak information. Therefore, in order to improve the PAPR suppression performance of windowed clipping, Is preferably varied in ascending and descending directions depending on the number of used subcarriers.

The peak suppression processing unit 300 detects the peak power PPL of the sample signal from the variable up / down sampling unit 200 for each section in which the peak exists, The peak power of the signal can be suppressed.

The signal conversion unit 400 may convert the digital signal from the peak suppression processing unit 300 into an analog signal.

In addition, the RF processor 500 may convert an analog signal from the signal converting unit 400 into an RF signal conforming to a predetermined communication protocol for wireless transmission.

2 is a block diagram of a peak suppression processing unit according to the first embodiment of the present invention.

2, the peak suppression unit 300 includes a signal power calculation unit 310 for calculating the power of each of the sample signals from the variable up / down sampling unit 200, A local peak detector 320 for detecting a peak power PPL in each of the periods in which the peak is present among the powers calculated by the local peak detector 310 and the peak power PPL detected by the local peak detector 320, A suppression factor determination unit 330 for determining a suppression factor SF according to each of the suppression factors SF and SF and a suppression factor determination unit 330 for generating a clipping window CW according to the suppression factor SF from the suppression factor determination unit 330, And a window clipping unit 340 for suppressing the peak power of the corresponding sample signal from the variable up / down sampling unit 200 by applying the clipping window CW.

1 and 2, the signal power calculation unit 310 may calculate the power of each of the sample signals from the variable up / down sampling unit 200. In this case, That is, the power (PL) can be obtained for the I signal (SI) and the Q signal (SQ) included in the sample signal as shown in the following equation (1).

[Equation 1]

PL = (SI) ² + (SQ) ²

The local peak detector 320 may detect the peak power PPL in each of the power PLs of the sample signal calculated by the signal power calculator 310. Here, a section means a section having only one peak.

The suppression factor determiner 330 may determine a suppression factor (SF) according to the peak power level PPL detected by the local peak detector 320. The suppression factor can be obtained by the following equation (2). Here, if the peak power is large, the suppression factor is also large.

For example, the suppression factor determiner 330 may compare the peak power PPL with the reference power PPL if the peak power PPL detected by the local peak detector 320 is greater than a predetermined reference power And the suppression factor SF can be determined according to the comparison result. If the suppression factor SF is applied, the signal can be transformed as shown in Equation (2).

&Quot; (2) "

The window clipping unit 340 generates a clipping window CW according to the suppression factor SF from the suppression factor determination unit 330 and applies the clipping window CW to the variable up / The peak power of the corresponding sample signal from the downsampling unit 200 can be suppressed. For example, the clipping window CW may be multiplied by the sample signal to suppress the peak power per section.

At this time, the window clipping unit 340 adjusts the size of the clipping window CW so that the distortion in the spectrum is minimized and the performance degradation in the bit error ratio is minimized. Can be adjusted according to the thickness of the corresponding sample signal having a peak. Here, the thickness of the sample signal means the time from the average power to the peak power and then again to the average power. In the case of being represented in the figure on the time axis, the peak signal shows how sharp or thick the signal is.

For example, when the thickness of the corresponding sample signal having the peak is large, the size of the clipping window (CW) can be increased according to the thickness of the thickness, while the thickness of the sample signal having the peak If the thickness is thin, the size of the clipping window (CW) can be reduced according to the thickness of the thickness.

As described above, at this time, the sample signal having the peak is most reduced in the characteristics of the window, and the sample signals on both sides of the peak sample signal are then reduced a lot, and then the sample signals on both sides are decreased . In this manner, all the sample signals entering the window section are proportionally reduced in proportion to one another, thereby preventing the rapid signal distortion and minimizing the distortion of the spectrum.

3 is a flowchart of a transmission method according to a second embodiment of the present invention.

Referring to FIG. 3, a transmission method according to a second embodiment of the present invention includes a step S100 of generating a digital signal, a sampling rate (SR) in real time according to the size of a signal bandwidth varying in real time, (S200) of sampling the digital signal from the signal generating step (S100) according to the sampling ratio (SR), and comparing the peak power (PPL) of the sample signal from the sampling step (S200) (S300) of detecting the peak power of the corresponding sample signal in accordance with the interval peak power (PPL), and a step (S300) of suppressing the peak power by using the analog signal (S400). ≪ / RTI >

In this case, referring to FIG. 1 and FIG. 3, first, in step S100 of FIG. 3, a digital signal including data to be transmitted can be generated by the digital generation unit 100 shown in FIG.

Next, in step S200 of FIG. 3, the sampling rate (SR) is varied in real time according to the size of the signal bandwidth varying in real time by the variable up / down sampling unit 200 shown in FIG. 1 , The digital signal from the generation step S100 of the digital signal may be sampled according to the sampling rate SR.

At this time, in the sampling step S200, a signal bandwidth which varies in real time is compared with a preset reference bandwidth, and a preset sampling ratio SR can be varied in real time according to the comparison result.

For example, in the sampling step S200, if the signal bandwidth is smaller than the reference bandwidth, the sampling rate SR may be lowered according to the bandwidth, and if the signal bandwidth is larger than the reference bandwidth, , The sampling rate (SR) may be increased according to the size of the bandwidth.

Next, in step S300 of FIG. 3, the peak suppression processing unit 300 shown in FIG. 1 detects the peak power PPL of the sample signal from the sampling step S200 on the basis of the interval in which the peak exists And the peak power of the corresponding sample signal can be suppressed according to the peak-to-peak power PPL.

Next, in step S400 of FIG. 3, the digital signal from the peak power suppressing step S300 may be converted into an analog signal by the signal converting unit 400 shown in FIG.

As described above, in the sampling step (S200) of the present invention, the sampling rate (SR) can be varied in real time according to the size of the signal bandwidth varying in real time. Referring to FIGS. 4 and 5 Explain.

4 is a first variable sequence view of a sampling rate according to an embodiment of the present invention.

Referring to FIG. 4, if the communication apparatus to which the present invention is applied is such that the communication bandwidth is 10 MHz band LTE, the bandwidth is first compared in the sampling step S200 (S211), and the signal bandwidth is pre- (S221). If the communication band is lower than 1.8 MHz, the sampling rate is reduced to 1/2 (S231), and the communication band is included in the range of 3.6 MHz to 7.2 MHz The sampling rate is increased to 2 times (2) (S241). If the communication band is higher than 7.2 MHz, the sampling rate can be increased to 4 times (4) (S251).

That is, assuming that the basic sampling rate in the LTE of the 10 MHz band is 1024 per symbol, when the bandwidth is smaller than 1.8 MHz, the sampling rate is reduced to 1/2 and down-sampling is performed to 512 per symbol. When the bandwidth is greater than 3.6 MHz and less than 7.2 MHz, the sampling rate is doubled to up to 2048 samples per symbol. If the bandwidth is greater than 7.2 MHz, the sampling rate can be increased to 4 times to up to 4096 samples. have. And when the bandwidth is 1.8MHz to 3.6MHz, 1024 can be used unchanged.

FIG. 5 is a second variable sequence view of a sampling rate according to an embodiment of the present invention. FIG. Referring to FIG. 5, when the communication apparatus to which the present invention is applied is that the bandwidth is 20 MHz band LTE, the bandwidth is first compared in the sampling step S200 (S212), and the signal bandwidth is set to 3.6 MHz (S222). If the communication bandwidth is within the range of 1.8 MHz to 3.6 MHz, the sampling rate is reduced to 1/2 (S232). If the communication bandwidth is lower than 3.6 MHz The sampling rate is reduced to 1/4 (S242). If the communication bandwidth is within the range of 7.2MHz to 14.4MHz, the sampling rate is increased to 2 times (2) (S252). If the communication bandwidth is higher than 14.4MHz, The ratio can be increased to 4 times (* 4) (S252).

That is, if the basic sampling rate in LTE in the 20 MHz band is 2048 per symbol, the uplink signal typically has much less bandwidth. Therefore, when the bandwidth is smaller than 1.8 MHz, the sampling rate is reduced to 1/4 and down-sampling is performed to 512 samples per symbol. When the bandwidth is larger than 1.8 MHz but less than 3.6 MHz, the sampling rate is reduced to 1/2 and down-sampling is performed to 1024 symbols. On the other hand, when the bandwidth is greater than 7.2 MHz and less than 14.4 MHz, the sampling rate is doubled to 4096 samples per symbol, and if the bandwidth is larger than 14.4 MHz, the sampling rate is increased to 4 times to 8192 samples. And when bandwidth is 3.6MHz to 7.2MHz, 2048 can be used unchanged.

6 is a flowchart of peak power suppression according to an embodiment of the present invention.

6, the peak power suppressing step S300 includes a step S310 of calculating the power of each of the sample signals from the sampling step S200, a step S310 of computing the power of each of the sample signals from the sampling step S200, A step S320 of detecting a peak power PPL in each of the periods in which the peak exists among the powers and a step S320 of detecting the suppression factor PPL according to each of the peak power PPL of each of the plurality of intervals detected in the peak power detection step S320. A clipping window CW is generated according to the suppression factor SF from the suppression factor determining step S330 and the clipping window CW is applied And suppressing the peak power of the corresponding sample signal from the sampling step S200 (S340).

In this case, referring to FIG. 2 and FIG. 6, in step S310 of FIG. 6, the power of each of the sample signals from the sampling step S200 is calculated by the signal power calculating unit 310 shown in FIG. Can be calculated.

Next, in step S320 of FIG. 6, the local peak detecting unit 320 shown in FIG. 2 calculates a peak power PPL (PPL) for each of the peaks among the powers calculated in the peak power calculating step S310 Can be detected.

Next, in step S330 of FIG. 6, the suppression factor determining unit 330 shown in FIG. 2 calculates the peak power PPL for each of the plurality of intervals detected in the peak power detecting step S320 The Suppression Factor (SF) can be determined.

More specifically, in the suppression factor determination step S330, if the peak power PPL detected in the peak power detection step S320 is greater than a preset reference power, the peak power PPL and the reference power PPL And the suppression factor SF can be determined according to the comparison result.

In step S340 of FIG. 6, the window clipping unit 400 shown in FIG. 2 generates a clipping window CW according to the suppression factor SF from the suppression factor determination step S330 And the clipping window CW is applied so that the peak power of the sample signal from the sampling step S200 can be suppressed.

For example, in the step of applying the clipping window (S340), the size of the clipping window (CW) may be adjusted so as to minimize distortion in a spectrum and to minimize performance degradation in a bit error ratio , And the thickness of the corresponding sample signal having the peak.

The transmission method according to the second embodiment of the present invention may include a step S500 of converting an analog signal from the signal conversion step S400 into an RF signal.

In this case, in step S500 of FIG. 6, the analog signal from the signal conversion step S400 may be converted into an RF signal conforming to a predetermined communication protocol.

7 is a descriptive graph of window clipping according to an embodiment of the present invention.

Referring to FIG. 7, in the clipping window application step (S340), when window clipping is applied, the sample signal G1 having a peak can be smoothly suppressed to be a desired signal G2. Here, the size of the window in the clipping window (GCW) can be adjusted according to the thickness of the sample signal having a peak to minimize distortion in the spectrum and minimize degradation in bit error rate (BER).

The PAPR suppression performance depends on the peak power information and the peak position information. Since the peak power is calculated by the difference between the peak power and the desired reference power, Peak Amplitude) information. Also, the PAPR suppression performance may depend on the peak position information, since accurate peak information minimizes signal distortion.

8 is a graph illustrating a fixed sampling rate for signals of different bandwidths. Referring to FIG. 8, G1 in FIG. 8 is an example of a thick peak signal having a small bandwidth having 120 subcarriers in an uplink channel in an LTE of 10 MHz band, G2 is an example of an LTE Is an example of a thin peak signal with a maximum bandwidth of 600 subcarriers in the uplink channel at < RTI ID = 0.0 >

In FIG. 8, when the sampling rate is not sufficiently high in the case of G2, the accurate peak power and position information can not be accurately measured.

9 is a graph showing the effect of increasing the PAPR and the sampling rate when the bandwidth is large.

Referring to FIG. 9, in a transmission apparatus to which 4QAM, 16QAM and 64QAM are applied, the original PAPR for each sample signal is as shown in G11, G21 and G31.

In Fig. 9, the PAPR suppression performance can be degraded when the bandwidth of the sample signal is large (600 at this time), as shown in G12, G22 and G32 in Fig. However, as shown in G13, G23, and G33 in FIG. 9, it is shown that the PAPR can be normalized again when the sampling ratio increases by a factor of four.

10 is an explanatory diagram of a peak suppression effect of a large sampling rate when the bandwidth is small.

Referring to FIG. 10, if the sampling rate is too large when the signal bandwidth is small, there is a disadvantage that the complexity of the operation becomes larger than necessary.

In a severe case, as shown in FIG. 10, the graph G1 of the sampling signal and the graph GCW of the clipping window show that when the size of the window is relatively small compared to the thickness of the sample signal, the PAPR suppression performance decreases .

That is, since window clipping starts from the peak center of the sample signal, as shown in FIG. 10, some component G2 of the sample signal can be suppressed, but the left peak component of the sample signal may not be suppressed properly.

100:
200: variable up / down sampling unit
300: peak suppression processing section
310: signal power calculation unit
320: Local peak detector
330: Suppression factor determination unit
340: window clipping section
400: Signal conversion unit
500: RF processor

Claims (19)

A signal generator for generating a digital signal;
A variable up / down sampling unit for varying a sampling rate in real time according to a size of a signal bandwidth varying in real time and sampling a digital signal from the signal generating unit according to the sampling rate;
A peak detector for detecting the peak power of the sample signal from the variable up / down sampling unit for each section in which the peak exists, and for suppressing the peak power of the sample signal using an inhibition factor determined according to the section peak power, Suppression processing unit; And
A signal conversion unit for converting a digital signal from the peak suppression processing unit into an analog signal; Lt; / RTI >
Wherein the peak suppression processing unit suppresses a corresponding peak power of the sample signal through a clipping window generated according to the suppression factor.
The apparatus of claim 1, wherein the variable up /
A baseband processor for comparing a signal bandwidth varying in real time with a preset reference bandwidth and varying a preset sampling rate in real time according to the comparison result.
3. The apparatus of claim 2, wherein the variable up /
Wherein when the signal bandwidth is smaller than the reference bandwidth, the sampling rate is lowered according to the signal bandwidth, and when the signal bandwidth is larger than the reference bandwidth, the sampling rate is increased according to the signal bandwidth. Band processor.
The apparatus according to claim 1 or 3,
A signal power calculation unit for calculating a power of each of the sample signals from the variable up / down sampling unit;
A local peak detector for detecting a peak power for each of the peaks among the powers calculated by the signal power calculator;
A suppression factor determiner for determining an inhibition factor according to the peak power per section detected by the local peak detector;
A window clipping unit for generating a clipping window in accordance with the suppression factor from the suppression factor determiner and for suppressing the peak power of the corresponding sample signal from the variable up /
/ RTI >
5. The apparatus according to claim 4,
And comparing the peak power with a reference power if the peak power detected by the local peak detector is greater than a predetermined reference power, and determining a suppression factor according to the comparison result.
6. The apparatus of claim 5, wherein the variable up /
And adjusts the size of the clipping window according to the thickness of the corresponding sample signal having the peak so as to minimize distortion in the spectrum and to minimize degradation in bit error rate.
A signal generator for generating a digital signal;
A variable up / down sampling unit for varying a sampling rate in real time according to a size of a signal bandwidth varying in real time and sampling a digital signal from the signal generating unit according to the sampling rate;
A peak detector for detecting the peak power of the sample signal from the variable up / down sampling unit for each section in which the peak exists, and for suppressing the peak power of the sample signal using an inhibition factor determined according to the section peak power, Suppression processing unit;
A signal conversion unit for converting a digital signal from the peak suppression processing unit into an analog signal; And
An RF processor for converting an analog signal from the signal converting unit into an RF signal; Lt; / RTI >
Wherein the peak suppression processing section suppresses a corresponding peak power of the sample signal through a clipping window generated according to the suppression factor.
8. The apparatus of claim 7, wherein the variable up /
A signal bandwidth that varies in real time is compared with a reference band width set in advance and the sampling rate set in advance is changed in real time according to the comparison result.
9. The apparatus of claim 8, wherein the variable up /
When the signal bandwidth is smaller than the reference bandwidth, the sampling rate is lowered according to the signal bandwidth, and when the signal bandwidth is larger than the reference bandwidth, Device.
8. The apparatus according to claim 7,
A signal power calculation unit for calculating a power of each of the sample signals from the variable up / down sampling unit;
A local peak detector for detecting a peak power for each of the peaks among the powers calculated by the signal power calculator;
A suppression factor determiner for determining an inhibition factor according to the peak power per section detected by the local peak detector;
A window clipping unit for generating a clipping window in accordance with the suppression factor from the suppression factor determiner and for suppressing the peak power of the corresponding sample signal from the variable up /
.
11. The apparatus of claim 10,
And comparing the peak power with a reference power if the peak power detected by the local peak detecting unit is greater than a predetermined reference power, and determining the suppression factor according to the comparison result.
12. The apparatus of claim 11, wherein the variable up /
And adjusts the size of the clipping window according to the thickness of the corresponding sample signal having the peak so as to minimize distortion in the spectrum and to minimize degradation in bit error rate.
Generating a digital signal;
Sampling the digital signal from the signal generation step according to the sampling rate, varying the sampling rate in real time according to the size of the signal bandwidth varying in real time;
Detecting a peak power of a sample signal from the sampling step in each section in which a peak exists and suppressing a corresponding peak power of the sample signal using an inhibition factor determined according to the peak power per section; And
Converting the digital signal from the peak power suppressing step into an analog signal; Lt; / RTI >
Wherein the step of suppressing the peak power suppresses a corresponding peak power of the sample signal through a clipping window generated according to the suppression factor.
14. The method of claim 13,
A transmission method for comparing a signal bandwidth varying in real time with a preset reference bandwidth and varying a preset sampling rate in real time according to the comparison result.
15. The method of claim 14,
When the signal bandwidth is smaller than the reference bandwidth, the sampling rate is lowered according to the signal bandwidth, and when the signal bandwidth is larger than the reference bandwidth, Way.
14. The method of claim 13,
Calculating power of each of the sample signals from the sampling step;
Detecting peak power for each of the peaks among the powers calculated in the peak power calculation step;
Determining a suppression factor according to the peak power detected in the peak power detection step;
Generating a clipping window in accordance with the suppression factor from the suppression factor determination step and applying the clipping window to suppress the peak power of the sample signal from the sampling step
.
17. The method of claim 16,
And comparing the peak power with a reference power if the peak power detected in the peak power detection step is greater than a preset reference power, and determining a suppression factor according to a result of the comparison.
18. The method of claim 17, wherein applying the clipping window comprises:
Wherein the size of the clipping window is adjusted according to the thickness of the corresponding sample signal having the peak so as to minimize distortion in the spectrum and minimize degradation in bit error rate.
14. The method of claim 13,
And converting the analog signal from the signal conversion step into an RF signal.

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